linux-kernel - Re: [PATCH v2] PCI: endpoint: Use EPC's device in dma_alloc_coherent/dma_free

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Message-ID: <acb4705b-6c44-78dc-a113-91b9fa251e30@arm.com>
Date:   Tue, 9 Jan 2018 12:46:29 +0000
From:   Robin Murphy <robin.murphy@....com>
To:     Kishon Vijay Abraham I <kishon@...com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Bjorn Helgaas <bhelgaas@...gle.com>
Cc:     linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        nsekhar@...com, Rob Herring <robh@...nel.org>,
        Christoph Hellwig <hch@....de>
Subject: Re: [PATCH v2] PCI: endpoint: Use EPC's device in
 dma_alloc_coherent/dma_free_coherent

On 19/12/17 08:36, Kishon Vijay Abraham I wrote:
> After commit 723288836628bc1c08 ("of: restrict DMA configuration"),
> of_dma_configure doesn't configure the coherent_dma_mask/dma_mask
> of endpoint function device (since it doesn't have a dt node associated
> with and hence no dma-ranges property), resulting in dma_alloc_coherent
> (used in pci_epf_alloc_space) to fail.
> 
> Fix it by making dma_alloc_coherent use EPC's device for allocating
> memory address as per discussion in [1]

Looks like cleaning up the API usage also cleans up the code nicely too, 
yay :)

Reviewed-by: Robin Murphy <robin.murphy@....com>

> [1] https://lkml.org/lkml/2017/10/24/26
> 
> Signed-off-by: Kishon Vijay Abraham I <kishon@...com>
> Cc: Robin Murphy <robin.murphy@....com>
> Cc: Rob Herring <robh@...nel.org>
> Cc: Christoph Hellwig <hch@....de>
> Tested-by: Cyrille Pitchen <cyrille.pitchen@...e-electrons.com>
> ---
> No change in patch. Only added "Tested-by" of Cyrille Pitchen.
> 
>   drivers/pci/endpoint/pci-epc-core.c | 10 ----------
>   drivers/pci/endpoint/pci-epf-core.c |  4 ++--
>   2 files changed, 2 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> index 42c2a1156325..cd7d4788b94d 100644
> --- a/drivers/pci/endpoint/pci-epc-core.c
> +++ b/drivers/pci/endpoint/pci-epc-core.c
> @@ -18,7 +18,6 @@
>    */
>   
>   #include <linux/device.h>
> -#include <linux/dma-mapping.h>
>   #include <linux/slab.h>
>   #include <linux/module.h>
>   #include <linux/of_device.h>
> @@ -371,7 +370,6 @@ EXPORT_SYMBOL_GPL(pci_epc_write_header);
>   int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf)
>   {
>   	unsigned long flags;
> -	struct device *dev = epc->dev.parent;
>   
>   	if (epf->epc)
>   		return -EBUSY;
> @@ -383,12 +381,6 @@ int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf)
>   		return -EINVAL;
>   
>   	epf->epc = epc;
> -	if (dev->of_node) {
> -		of_dma_configure(&epf->dev, dev->of_node);
> -	} else {
> -		dma_set_coherent_mask(&epf->dev, epc->dev.coherent_dma_mask);
> -		epf->dev.dma_mask = epc->dev.dma_mask;
> -	}
>   
>   	spin_lock_irqsave(&epc->lock, flags);
>   	list_add_tail(&epf->list, &epc->pci_epf);
> @@ -503,9 +495,7 @@ __pci_epc_create(struct device *dev, const struct pci_epc_ops *ops,
>   	INIT_LIST_HEAD(&epc->pci_epf);
>   
>   	device_initialize(&epc->dev);
> -	dma_set_coherent_mask(&epc->dev, dev->coherent_dma_mask);
>   	epc->dev.class = pci_epc_class;
> -	epc->dev.dma_mask = dev->dma_mask;
>   	epc->dev.parent = dev;
>   	epc->ops = ops;
>   
> diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
> index ae1611a62808..95ccc4b8a0a2 100644
> --- a/drivers/pci/endpoint/pci-epf-core.c
> +++ b/drivers/pci/endpoint/pci-epf-core.c
> @@ -99,7 +99,7 @@ EXPORT_SYMBOL_GPL(pci_epf_bind);
>    */
>   void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar)
>   {
> -	struct device *dev = &epf->dev;
> +	struct device *dev = epf->epc->dev.parent;
>   
>   	if (!addr)
>   		return;
> @@ -122,7 +122,7 @@ EXPORT_SYMBOL_GPL(pci_epf_free_space);
>   void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar)
>   {
>   	void *space;
> -	struct device *dev = &epf->dev;
> +	struct device *dev = epf->epc->dev.parent;
>   	dma_addr_t phys_addr;
>   
>   	if (size < 128)
>